Reduce number of queries in blog_page (#9857)

CONTRIBUTORS.rst

@@ -679,6 +679,7 @@ Contributors
 * Vallabh Tiwari
 * dr-rompecabezas
 * Rishabh jain
+* Jhonatan Lopes
 
 Translators
 ===========

docs/getting_started/tutorial.md

@@ -694,14 +694,16 @@ Edit one of your `BlogPage` instances, and you should now be able to tag posts:
 To render tags on a `BlogPage`, add this to `blog_page.html`:
 
 ```html+django
-{% if page.tags.all.count %}
-    <div class="tags">
-        <h3>Tags</h3>
-        {% for tag in page.tags.all %}
-            <a href="{% slugurl 'tags' %}?tag={{ tag }}"><button type="button">{{ tag }}</button></a>
-        {% endfor %}
-    </div>
-{% endif %}
+{% with tags=page.tags.all %}
+    {% if tags %}
+        <div class="tags">
+            <h3>Tags</h3>
+            {% for tag in tags %}
+                <a href="{% slugurl 'tags' %}?tag={{ tag }}"><button type="button">{{ tag }}</button></a>
+            {% endfor %}
+        </div>
+    {% endif %}
+{% endwith %}
 ```
 
 Notice that we're linking to pages here with the builtin `slugurl`